Constant speed responsive spark controller

ABSTRACT

A vacuum advance for an ignition distributor of an internal combustion engine has a dual vacuum operator to position a spark advance lever in a main spark advance position and an additional boost spark advance position in accordance with vehicle speed conditions to produce improved fuel economy. The dual operator includes a main vacuum operator that has a signal port connected to the intake manifold of an engine to advance the spark lever to a main spark advance position during engine operation through a lost motion connector. A solenoid vacuum control valve is selectively energized under the control of a differential speed sensor to vent the vacuum chamber of a boost vacuum operator when the vehicle is accelerated or decelerated so as to maintain the spark advance lever in its first control position. When constant vehicle speed is attained, the speed sensor conditions the solenoid vacuum valve to direct a vacuum signal from the intake manifold to the boost vacuum unit to produce a lost motion shift to effect further advance of the spark advance lever thereby to produce an improved fuel economy.

United States Patent Stacey, Jr.

1 June 10, 1975 1 1 CONSTANT SPEED RESPONSIVE SPARK CONTROLLER [75] Inventor: Thomas A. Stacey. .]r., Fenton,

Mich.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Apr. 25, 1974 [21] Appl. No.: 463,877

[52] U.S. Cl 123/117 A; 123/1465 A [51] Int. Cl. F02p 5/08 [58] Field of Search 123/117 A, 117 R, 146.5 A

[56] References Cited UNITED STATES PATENTS 3,515,105 6/1970 Soeters 123/117 A 3,638,627 2/1972 Beard r r r 123/117 A 3,727,596 4/1973 Panhardm 123/117 A 3,780,713 12/1973 Julian .1 123/117 A 3,788,291 1/1974 Wu 123/117 A Primary Examiner--Charles .l. Myhre Assistant Examiner-Tony Argenbright Attorney, Agent, or Fz'rm.l. C. Evans 1 1 ABSTRACT A vacuum advance for an ignition distributor of an internal combustion engine has a dual vacuum operator to position a spark advance lever in a main spark advance position and an additional boost spark advance position in accordance with vehicle speed conditions to produce improved fuel economy. The dual operator includes a main vacuum operator that has a signal port connected to the intake manifold of an engine to ad vance the spark lever to a main spark advance position during engine operation through a lost motion connector. A solenoid vacuum control valve is selectively energized under the control of a differential speed sensor to vent the vacuum chamber of a boost vacuum operator when the vehicle is accelerated or decelerated so as to maintain the spark advance lever in its first control position. When constant vehicle speed is attained, the speed sensor conditions the solenoid vacuum valve to direct a vacuum signal from the intake manifold to the boost vacuum unit to produce a lost motion shift to effect further advance of the spark advance lever thereby to produce an improved fuel economy,

4 Claims, 1 Drawing Figure CONSTANT SPEED RESPONSIVE SPARK CONTROLLER 1 l his invention relates to spark advance control systerm for the ignition distributor of an internal combus tion engine and more particularly to multiple advance spark control systems for the distributor of an internal combustion engine.

It is recognized that spark advance control of an ignition distributor to the spark plugs in an internal combustion engine can affect engine performance and fuel economy.

Existing systems include the provision of a vacuum operator responsive to intake manifold vacuum to produce a fixed spark advance to reduce the throttle valve opening required to produce a given vehicle operating condition.

Under certain operating conditions, for example when the vehicle is being operated at a constant speed, still further improvement in vehicle performance can be obtained by provision of an additional advance of the spark from the distributor to the engine spark plugs.

Accordingly, an object of the present invention is to improve vehicle performance and fuel economy by the provision ofan improved two-stage vacuum advance of spark in an ignition distributor for an internal combustion engine including means for producing a main spark advance during vehicle acceleration and deceleration and means for producing an additional spark advance during road load operation under constant vehicle speed conditions.

Still another object of the present invention is to pro duce additional spark advance in the ignition system for an internal combustion engine only during road load or constant speed conditions and to do so by means operatively connected to the existing spark advance lever for the ignition distributor for the engine.

Still another object of the present invention is to improve vehicle performance and fuel economy by use of a road load responsive vacuum spark advance system having a dual diaphragm vacuum operator unit including a main diaphragm operative to produce normai spark advance to avoid engine detonations and to produce acceptable engine emission characteristics and with the further provision of a boost diaphragm supplied with a boost vacuum signal by solenoid operated vacuum valve means wherein the solenoid is conditioned to supply the signal to the boost diaphragm when speed sensor means detects a constant vehicle speed condition and wherein the boost diaphragm is vented to maintain the normal spark advance under vehicle acceleration or deceleration. The boost diaphragm producing an additional spark advance of the distributor when the vacuum signal is directed thereto to produce improved engine combustion with resultant improvement in fuel economy.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

The single FIGURE ofthe drawing is directed to a diagrammatic illustration of a road load responsive vacuum spark system including a dual diaphragm unit shown in vertical section and a solenoid vacuum valve in vertical section.

In the drawing, a system 10 is illustrated which produces additional spark advance of an ignition distribu tor for an internal combustion engine during road load operations. i.e., conditions wherein the vehicle speed is constant. The system includes a dual diaphragm vacuum operator 12 having a main, vacuum energized. diaphragm operator unit 14 and a boost, vacuum energized, operator unit 16. The main diaphragm operator 14 includes a metal housing with first concave member 18 secured to an oppositely dished member 20 by means of a peripheral flange 22 thereon bent into secured engagement with a radially outwardly directed flange 24 on the member 18.

The outer periphery of a flexible diaphragm 26 is secured between the flanges 22, 24 and divides the hous ing into an atmospheric chamber 28 and a vacuum chamber 30. The diaphragm 26 has a piston 32 secured thereto by a rivet 34 that additionally is connected to one end of a U-shaped shaft connector link 36.

The link 36 is aligned with a central opening 38 in the housing member 20 for movement inwardly and outwardly of the atmospheric chamber 28. It includes a bore 40 which slidably receives one end of a shaft 42. The shaft 42 carries a snap ring 44 on one end thereof that is engaged by an end 46 oflink 36 having the bore 40 therein upon movement of the flexible diaphragm 26 leftwardly as viewed in the drawing. The opposite end of the operating shaft 42 is connected to a flexible diaphragm 48 of operator 16. The outer periphery of diaphragm 48 is held between a radially outwardly directed flange 50 on a first concave housing member 52 and a radially outwardly directed flange 54 on a second concave housing member 56 of the booster vacuum operator unit 16. The flange 54 is bent over the flange 50 to secure the flexible diaphragm 48 therebetween.

The connection of the shaft 42 to the flexible diaphragm 48 is at a tapered shoulder 58 on the shaft 42 which engages a piston 60 that backs the flexible diaphragm 48. The flexible diaphragm 48 and housing members 52, 56 cooperate to define a vacuum signal chamber 62 on one side thereof and an atmospheric chamber 64 on the opposite side thereof. The shaft 42 also includes a head 66 thereon that secures a bent end 68 of a spark advance lever 70 to the diaphragm 48 for movement therewith. The lever 70 is connected at the opposite end thereof to an ignition distributor so as to position contact breaker points therein, shown diagrammatically at 71, with respect to distributor cam means, shown diagrammatically at 73, for producing a predetermined control of a spark advance.

In the illustrated arrangement, only a fragmentary portion of a distributor housing 72 is shown. It includes a port 74 and a segment ofa movable breaker plate 76 with an extension 78 thereon directed through the port 74 in a rest position shown in solid lines; a main spark advance position is shown in dotted lines at 78a and a boost spark advance position is shown at 78b. When the extension 78 of the breaker plate 76 is located as shown at 78a, 78b in the drawing, the contact set carried on plate 76 is advanced to produce first and second spark advance from the distributor.

The dual diaphragm vacuum unit 12 is supported with respect to the distributor housing by suitable fastening means such as a pair of studs 80, 82 fixedly secured to the end of the housing member 56 and the boost operator 16 is connected to the main vacuum operator 14 by a post 84 having a threaded end 86 thereon directed through a bore 88 in the housing member where it is fastened by suitable means such as a nut 90. The boost operator unit 16 includes a lost motion connection between the shaft 42 and the housing member 52 defined by a conically configured open ended, hollow resilient element 92 having a large diameter end 94 thereon secured in an opening 96 in the housing member 52 coaxially of the opening 38 in the housing member 20. The element 92 includes a reversely bent small diameter end portion 98 with an annular bead 100 fixedly secured within an annular groove 102 on the shaft 42.

By virtue of the aforedescribed structure, when a vacuum signal is directed to the main vacuum operator 14 through a vacuum signal port 104 therefrom from suitable means such as a conduit 106 connected between the signal port 104 and a port 108 to the intake manifold 109 of an internal combustion engine, the main vacuum operator 14 will have its flexible diaphragm 26 shifted against the housing member 18. This causes the shaft 42 and the lever 70 to be moved leftwardly as viewed in the drawing to cause the breaker plate extension 78 to assume its main spark advance position shown at 78a. Main vacuum spark advances in the order of 20 maximum are found to avoid detonation and to produce adequate exhaust emissions follow ing an engine warm-up phase of operation.

The present invention recognizes that fuel economy can be gained by the provision of a further vacuum advance under road load operating conditions where the vehicle speed is substantially constant. An optimum cut in point for additional spark advance is a rate of acceleration or deceleration in the order of twenty revolutions per minute per second. In the present invention, a differential speed sensor unit 110 differentiates a speed signal from a pick-up 112 on the ignition coil which senses a rate of change in engine RPM.

When the engine speed is substantially constant, i.e., when engine acceleration or deceleration is less than 20 revolutions per minute per second, a signal is produced through input 114 to the sensor 110 to condition a diagrammatically illustrated relay switch 116 therein to complete a circuit from the power source represented by the battery 118 to an input terminal 120 of a solenoid operated vacuum control valve 122. The vacuum control valve 122, during vehicle speed changes, is deenergized so as to locate a spool valve 124 in the illustrated solid line position. This communicates a signal conduit 126 to a signal port 128 to the booster vacuum unit 16 to vent chamber 62 therein with atmosphere through a valve port 129.

When the chamber 62 is in communication with atmosphere, the only movement of the spark advance lever 70 is affected by the main vacuum operator 14 which shifts leftwardly when intake manifold is applied thereto to position lever 70 in its main advance position at 78a. However, when a substantially constant vehicle speed is detected by the pick-up 112, the switch 116 will close to energize a coil 130 thereby to shift the spool valve 124 from its solid line position to a dotted line position in the drawing wherein the signal conduit 126 is communicated with a vacuum line 128 connected between the intake manifold port 108 and a vacuum port 132 in the valve 122. When a vacuum signal is directed to the vacuum signal port 128, the flexible diaphragm 48 is shifted still further to the left from the position that is produced by control movement of the main vacuum operator 14. The resilient element 92 will have the small diameter end 98 collapsed in a telescoped fashion into the large diameter end 94 thereof and the shaft 42 will freely slide through the bore 40 into the chamber 28 to produce an additional stepped advance of the spark advance lever so as to cause the breaker plate extension 78 to move to its boost spark advance position at 78b.

in one working embodiment. when the differential speed sensor senses an input signal from pickup 1 12 reflecting vehicle engine acceleration rates greater than twenty RPM per second, the switch 116 is opened and the spool 124 of the valve 122 assumes its solid line position thereby to vent the vacuum chamber 62 of the boost vacuum operator 16. This will cause the resilient element 92 to apply a bias to the shaft 42 to shift it to the right as viewed in the drawings until the snap ring 44 engages the bracket leg 46. The flexible diaphragm 48 and the spark advance lever 70 connected thereto are moved from the boost spark advance position shown at 78b to the main spark advance position shown at 78a.

When the engine is stopped. the vacuum chamber 30 of the main vacuum unit 14 is vented to cause the flexible diaphragm 26 to assume the position shown in the drawing and the flexible diaphragm 48 and element 92 to position the lever 70 in its start position at 78.

The system thus provides additional spark advance during road load operation when vehicle speed is substantially constant and detonation tendency is minimized. The system produces a measurable gain in fuel economy at normal highway speeds in the order of 50 to 60 MPH when the additional advance is present. There is a slight increase in nitrous oxide emissions, but hydrocarbon and carbon monoxide emissions are unef fected. A cut-in point of the solenoid vacuum valve 122 produced by engine acceleration less than twenty RPM per second has the least effect on NO, emissions.

While the embodiments of the present invention, as herein disclosed, constitute a preferred form, it is to be understood that other forms might be adopted.

What is claimed is:

1. A spark advance controller for the ignition distributor in an internal combustion engine having a contact set carried by a movable breaker plate to adjust the contact set with respect to distributor cam means to control the spark advance from the distributor to spark plugs for igniting a combustible air-fuel mixture in the cylinders of the internal combustion engine comprising: main vacuum operator means including a movable diaphragm defining a main vacuum chamber, boost vacuum operator means including a second movable diaphragm forming a boost vacuum chamber, each of said main and boost vacuum chambers including a signal port thereto, means for communicating said main vacuum chamber port with the intake manifold of an internal combustion engine, a distributor spark advance lever having first and second control positions for producing a staged advance of a spark from a distributor, coupling means for connecting said spark advance lever to each of said first and second movable diaphragms, said first movable diaphragm and said coupling means being responsive to reduced intake manifold pressure produced during engine operation to move said advance lever into its first control position to effect a first spark advance from the engine distributor, and signal producing means for directing a boost vacuum signal to said boost vacuum chamber upon the occurrence of a constant vehicle speed to operate said coupling means to move said distributor lever into its second control position thereby to produce a further advance of spark under road load, constant vehicle speed conditions to produce a resultant improvement in fuel economy without engine detonation.

2. A spark advance controller for an ignition distributor of the type having a movable breaker plate carrying a contact set with respect to a distributor cam to control the timing of ignition current to spark plugs for igniting a combustible air-fuel mixture in the cylinder of an internal combustion engine comprising: a spark advance lever having a main spark advance position and a boost spark advance position, vacuum operator means coupled to said spark advance lever including first and second chambers therein each having a movable diaphragm therein responsive to changes in pressure in the chamber to effect a staged location of said spark advance lever in its main spark advance and boost spark advance control positions, means for com municating one of said chambers with the intake manifold pressure of an internal combustion engine to position said spark advance lever in its main spark advance position, boost signal means for directing a vacuum signal to the other of said chambers only when vehicle speed is within a predetermined range of accelerative or decelerative change, said vacuum operator means being responsive to a boost signal directed thereto to position said spark advance lever in its boost spark advance location so as to produce improved combustion of the air-fuel charge in an internal combustion engine under road load vehicle operation with resultant improvement of fuel economy.

3. A spark advance controller for an ignition distributor of the type having a movable breaker plate carrying a contact set with respect to a distributor cam to control the timing of ignition current to spark plugs for igniting a combustible air-fuel mixture in the cylinder of an internal combustion engine comprising: a spark advance lever having a main spark advance position and a boost spark advance position, vacuum operator means coupled to said spark advance lever including first and second chambers therein each having a movable diaphragm therein responsive to changes in pressure in the chamber to effect a staged location of said spark advance lever in its main spark advance and boost spark advance control positions, means for communicating one of said chambers with the intake manifold pressure of an internal combustion engine to position said spark advance lever in its main spark advance position, boost signal means including a solenoid vacuum valve having a vacuum port therein in communication with intake manifold vacuum, a vent port therein in communication with atmosphere and a signal port in communication with the other chamber of said vacuum operator means, electrically energizable valve means for selectively communicating said vacuum port and said vent port with said signal port, speed sensor means responsive to vehicle operation within a predetermined range of speed change to condition said energizable valve means to communicate intake manifold vacuum with said signal port to condition said vacuum operator means to position said spark advance lever into its boost spark advance position, said speed sensor means being operative when vehicle speed is changing to communicate said signal port with said vent to cause said spark advance lever to assume its main spark advance position whereby ignition spark advance is responsive to constant speed vehicle operation and decel eration and acceleration to produce an improved combustion and resultant increase in fuel economy.

4. In a spark advance controller for an ignition distributor in an internal combustion engine of the type having a movable breaker plate for moving a contact set with respect to a distributor cam to control spark advance therefrom, the improvement comprising: a dual vacuum operator including a first vacuum chamber formed in part by a first movable diaphragm, a second vacuum chamber formed in part by a second movable diaphragm, a spark advance lever directly coupled to one of said movable diaphragms, lost motion connection means for coupling the other of said movable diaphragrns to said spark advance lever, means for directly communicating said first vacuum chamber with the intake manifold of an internal combustion engine to produce a predetermined shift of said first movable diaphragm through said lost motion connection means and said second movable diaphragm so as to position said spark advance lever in a first spark advance position, valve means for selectively directing a boost vacuum signal from the intake manifold or a vent signal to said second vacuum chamber, said valve means having a first operating position wherein the second vacuum chamber is vented when the spark advance lever is in its first control position, said valve means having a second position for communicating said second vacuum chamber with the vacuum signal to produce a further movement of said second movable diaphragm with said lost motion connection decoupling said second diaphragm from said first diaphragm so as to position said spark advance lever in a second additional spark advance position and means for conditioning said valve means into its second operating position when the vehicle is operated under substantially constant speed conditions and into its first operating position when the vehicle is accelerated or decelerated above a predetermined rate thereby to maintain the first predetermined spark advance position under deceleration and acceleration and to maintain the spark advance lever in its more advance second control position whenever the vehicle is operated under substantially constant speed conditions thereby to improve fuel economy. 

1. A spark advance controller for the ignition distributor in an internal combustion engine having a contact set carried by a movable breaker plate to adjust the contact set with respect to distributor cam means to control the spark advance from the distributor to spark plugs for igniting a combustible air-fuel mixture in the cylinders of the internal combustion engine comprising: main vacuum operator means including a movable diaphragm defining a main vacuum chamber, boost vacuum operator means including a second movable diaphragm forming a boost vacuum chamber, each of said main and boost vacuum chambers including a signal port thereto, means for communicating said main vacuum chamber port with the intake manifold of an internal combustion engine, a distributor spark advance lever having first and second control positions for producing a staged advance of a spark from a distributor, coupling means for connecting said spark advance lever to each of said first and second movable diaphragms, said first movable diaphragm and said coupling means being responsive to reduced intake manifold pressure produced during engine operation to move said advance lever into its first control position to effect a first spark advance from the engine distributor, and signal producing means for directing a boost vacuum signal to said boost vacuum chamber upon the occurrence of a constant vehicle speed to operate said coupling means to move said distributor lever into its second control position thereby to produce a further advance of spark under road load, constant vehicle speed conditions to produce a resultant improvement in fuel economy without engine detonation.
 2. A spark advance controller for an ignition distributor of the type having a movable breaker plate carrying a contact set with respect to a distributor cam to control the timing of ignition current to spark plugs for igniting a combustible air-fuel mixture in the cylinder of an internal combustion engine comprising: a spark advance lever having a main spark advance positIon and a boost spark advance position, vacuum operator means coupled to said spark advance lever including first and second chambers therein each having a movable diaphragm therein responsive to changes in pressure in the chamber to effect a staged location of said spark advance lever in its main spark advance and boost spark advance control positions, means for communicating one of said chambers with the intake manifold pressure of an internal combustion engine to position said spark advance lever in its main spark advance position, boost signal means for directing a vacuum signal to the other of said chambers only when vehicle speed is within a predetermined range of accelerative or decelerative change, said vacuum operator means being responsive to a boost signal directed thereto to position said spark advance lever in its boost spark advance location so as to produce improved combustion of the air-fuel charge in an internal combustion engine under road load vehicle operation with resultant improvement of fuel economy.
 3. A spark advance controller for an ignition distributor of the type having a movable breaker plate carrying a contact set with respect to a distributor cam to control the timing of ignition current to spark plugs for igniting a combustible air-fuel mixture in the cylinder of an internal combustion engine comprising: a spark advance lever having a main spark advance position and a boost spark advance position, vacuum operator means coupled to said spark advance lever including first and second chambers therein each having a movable diaphragm therein responsive to changes in pressure in the chamber to effect a staged location of said spark advance lever in its main spark advance and boost spark advance control positions, means for communicating one of said chambers with the intake manifold pressure of an internal combustion engine to position said spark advance lever in its main spark advance position, boost signal means including a solenoid vacuum valve having a vacuum port therein in communication with intake manifold vacuum, a vent port therein in communication with atmosphere and a signal port in communication with the other chamber of said vacuum operator means, electrically energizable valve means for selectively communicating said vacuum port and said vent port with said signal port, speed sensor means responsive to vehicle operation within a predetermined range of speed change to condition said energizable valve means to communicate intake manifold vacuum with said signal port to condition said vacuum operator means to position said spark advance lever into its boost spark advance position, said speed sensor means being operative when vehicle speed is changing to communicate said signal port with said vent to cause said spark advance lever to assume its main spark advance position whereby ignition spark advance is responsive to constant speed vehicle operation and deceleration and acceleration to produce an improved combustion and resultant increase in fuel economy.
 4. In a spark advance controller for an ignition distributor in an internal combustion engine of the type having a movable breaker plate for moving a contact set with respect to a distributor cam to control spark advance therefrom, the improvement comprising: a dual vacuum operator including a first vacuum chamber formed in part by a first movable diaphragm, a second vacuum chamber formed in part by a second movable diaphragm, a spark advance lever directly coupled to one of said movable diaphragms, lost motion connection means for coupling the other of said movable diaphragms to said spark advance lever, means for directly communicating said first vacuum chamber with the intake manifold of an internal combustion engine to produce a predetermined shift of said first movable diaphragm through said lost motion connection means and said second movable diaphragm so as to position said spark advance lever in a first spark advance position, valve means for selectively directing a boost vacuum Signal from the intake manifold or a vent signal to said second vacuum chamber, said valve means having a first operating position wherein the second vacuum chamber is vented when the spark advance lever is in its first control position, said valve means having a second position for communicating said second vacuum chamber with the vacuum signal to produce a further movement of said second movable diaphragm with said lost motion connection decoupling said second diaphragm from said first diaphragm so as to position said spark advance lever in a second additional spark advance position and means for conditioning said valve means into its second operating position when the vehicle is operated under substantially constant speed conditions and into its first operating position when the vehicle is accelerated or decelerated above a predetermined rate thereby to maintain the first predetermined spark advance position under deceleration and acceleration and to maintain the spark advance lever in its more advance second control position whenever the vehicle is operated under substantially constant speed conditions thereby to improve fuel economy. 